Effect of free electrons on nanoparticle charging in a negative direct current corona charger

A 2D numerical model is proposed to study the electric charge that will provide nanoparticles within a cylindrical corona discharge with a wire along the axis. The wire-tube electrical charger is subjected to a negative DC voltage and filled with air at atmospheric pressure at ambient temperature. A numerical application is given by considering spherical nanoparticles with a diameter of 65 nm within a wire-tube charger with a radius of 2 cm and 26cm in length. Numerical results obtained are in very good agreement with the experimental data. These results show that free electrons contribute greatly to the electrical charging efficiency mechanism of the corona charger in particular at high Ntproduct, which explains very well the large discrepancy found in earlier models which not considered electrons.